The association of employee and workplace characteristics with work disability trajectories before, during and after psychotherapy in occupational health services – a Finnish register-based longitudinal study

Depression and anxiety disorders are the leading causes of work disability in most developed countries. Psychotherapies are evidence-based treatments for these disorders, but evidence of the psychotherapy effects on changes in work disability remains limited. This study examined changes in work disability in patients receiving psychotherapy and matched controls and their associations with employee and employer-related factors. We used register-based data from Terveystalo Plc., Finland’s largest occupational health service provider, linked with national registers (Statistics Finland, Social Insurance Institution). The study included patients who received primary care-level psychotherapy ( N = 3,912) between 2018 and 2021, matched with controls ( N = 11,733) using propensity scores. Group-based trajectory modelling identified work disability patterns based on three-month means of mental health-related sickness absence day intervals. Multinomial logistic regression assessed associations between sickness absence trajectory membership and baseline sociodemographic, clinical, and employer characteristics. Three distinct work disability trajectory groups emerged: a group including those employees with a highly increasing level of work disability (6% of the population), ranging from 17 to 1 day of work disability and those with a slightly increasing (7% of the population) level of work disability ranging from 5 to 1 days of work disability. In both groups, the level of work disability peaked around psychotherapy onset and decreased after it. The third group, stable low (87% of the population), included those with nearly no work disability throughout the study. In multinomial regression models, history of mental disorders, related sickness absences, and somatic and psychiatric comorbidity were associated with the likelihood of belonging to either of the adverse work disability trajectory groups. Psychotherapy may decrease long-term work disability, especially among individuals with a high level of baseline work disability. Those with a previous mental disorder burden and related work disability require special attention to enable timely treatment to prevent prolonged work disability.